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Material property and quality control specifications for elastomeric concrete used at bridge deck joints : final report

Material property and quality control specifications for elastomeric concrete used at bridge deck joints : final report - Page 48

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however, NCDOT expressed concerns about the patching material debonding overtime due to the cyclic
effects experienced in the tire path. Therefore, specimens were only obtained on the shoulder.
Drilling was performed in a gradual manner to prevent any form of damage to the cored specimens.
There were two signals indicating that the full depth of the elastomeric concrete had been penetrated. The
first being that a distinct difference in the drilling could be felt once the drill made contact with the
underlying concrete. The drill would begin to shake much more once the concrete layer was reached.
Also, the water that was being pumped down to the point of contact between the bit and the elastomeric
concrete would turn light- grey indicating that the concrete had been struck by the bit. The drill would be
slowly elevated once the drill completely penetrated the elastomeric concrete. Once the drilling bit was
elevated back to its at- rest position, wedges were used to slowly loosen the specimens from the concrete
as can be seen in Figure 5- 9.
Figure 5- 9. Removal of core samples
Once all of the specimens were “ popped” out of the joint, the remaining debris and water were vacuumed
out of the void. This would ensure that the patching material ( ideally the same elastomeric concrete or a
similar patching material) would not be affected by considerable moisture content within the joint.
5.3.2 Specimen Preparation
When all coring was complete, the cylindrical 2.5” and 3” specimens needed to be modified for the
appropriate testing method. The 2.5” cores would be used for the tensile splitting strength and impact
resistance specimens. These would simply need to be saw- cut to the correct dimensions using a dry
cutting diamond blade, typically used for normal concrete. The tensile splitting specimens were cut into
sections 1.5” thick, while the impact resistance specimens were cut into discs .375” thick. The 3”
diameter cores would be used for compressive strength specimens and consisted of more complex cutting.
In order to keep the dimensions of the compressive strength specimens constant from previous phase
testing, 2” cubes would need to be rendered. The cubes were carefully produced by first cutting core
specimens into 2” thick sections. A 2” x 2” template was used to define the cross- section on the top face

41
however, NCDOT expressed concerns about the patching material debonding overtime due to the cyclic
effects experienced in the tire path. Therefore, specimens were only obtained on the shoulder.
Drilling was performed in a gradual manner to prevent any form of damage to the cored specimens.
There were two signals indicating that the full depth of the elastomeric concrete had been penetrated. The
first being that a distinct difference in the drilling could be felt once the drill made contact with the
underlying concrete. The drill would begin to shake much more once the concrete layer was reached.
Also, the water that was being pumped down to the point of contact between the bit and the elastomeric
concrete would turn light- grey indicating that the concrete had been struck by the bit. The drill would be
slowly elevated once the drill completely penetrated the elastomeric concrete. Once the drilling bit was
elevated back to its at- rest position, wedges were used to slowly loosen the specimens from the concrete
as can be seen in Figure 5- 9.
Figure 5- 9. Removal of core samples
Once all of the specimens were “ popped” out of the joint, the remaining debris and water were vacuumed
out of the void. This would ensure that the patching material ( ideally the same elastomeric concrete or a
similar patching material) would not be affected by considerable moisture content within the joint.
5.3.2 Specimen Preparation
When all coring was complete, the cylindrical 2.5” and 3” specimens needed to be modified for the
appropriate testing method. The 2.5” cores would be used for the tensile splitting strength and impact
resistance specimens. These would simply need to be saw- cut to the correct dimensions using a dry
cutting diamond blade, typically used for normal concrete. The tensile splitting specimens were cut into
sections 1.5” thick, while the impact resistance specimens were cut into discs .375” thick. The 3”
diameter cores would be used for compressive strength specimens and consisted of more complex cutting.
In order to keep the dimensions of the compressive strength specimens constant from previous phase
testing, 2” cubes would need to be rendered. The cubes were carefully produced by first cutting core
specimens into 2” thick sections. A 2” x 2” template was used to define the cross- section on the top face